<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>
<body>
  
<div id="app">
  <!-- 使用v-model将input标签与h2标签进行双向绑定 -->
  <input type="text" v-model="message">

  <h2>{{message}}</h2>
</div>

<script src="../js/vue.js"></script>
<script>
  const app = new Vue({
    el: '#app',
    data:
    {
      message: 'Hello World'
    }
  })  
</script>

</body>
</html>